Table 3.

Subgroup and Sensitivity Analyses

	k	N	SMD (95% CI)	P Value	I 2 (%)
Fixed effects model	16	1274	0.53 (0.41, 0.65)	<.001	87.3
Exclusion of two trialsa	14	1121	0.56 (0.38, 0.74)	<.001	51.7
Studies using plasma samplesa	9	647	0.60 (0.36, 0.85)	<.001	56.5
Studies using serum samplesa	5	474	0.48 (0.22, 0.74)	<.001	45.7
High-quality studies	4	392	0.82 (0.03, 1.61)	.04	92.2
High- and fair-quality studies	14	1140	0.63 (0.38, 0.88)	<.001	75.8

Note: CI, confidence interval; k, number of studies; N, number of participants; SMD, standardized mean difference.

^aAfter excluding two trials with implausible results.^11,13